EGF-induced signaling and increased beta-catenin transactivation have been reported separately to correlate with tumor formation and development. However, the exact relationship between EGF-induced signaling and increased beta-catenin transactivation is not clear. Our preliminary data show that EGF treatment disrupts cell-cell junctions of tumor cells overexpressing EGFR and increases beta-catenin transactivation. Moreover, EGF-induced beta-catenin transactivation is regulated through caveolin-1- and Ras/Raf/ERK-dependent pathways. ERK MAP kinase binds to beta-catenin, leading to our exploration into the mechanism of EGF-induced beta-catenin transactivation and its role in the development of human cancers that have aberrantly overexpress EGFR. In Aim 1, we will analyze the relationship between ERK and beta-catenin in response to EGF treatment and the role of this relationship in beta-catenin nuclear translocation and transactivation. Aim 2 focuses on understanding the mechanism of ERK-independent but caveolin-1-dependent regulation of beta-catenin transactivation and the mechanism of beta-catenin endocytosis in response to EGF stimulation. In Aim 3, we plan to determine the role of beta-catenin transactivation in EGFR-related tumor growth and metastasis. Understanding the interplay between EGFR and Wnt signaling components will provide an important basis for understanding tumor cell invasion and metastasis, which may provide novel targets and approaches for developing more effective cancer therapies.